Which laboratory finding is typically associated with allergic reactions?

Increased eosinophils are typically associated with allergic reactions. Eosinophils are a type of white blood cell that plays a significant role in the body's immune response, particularly in combating parasitic infections and mediating allergic reactions. During an allergic response, substances such as pollen, dust mites, or certain foods can trigger the immune system, leading to an increased production of eosinophils. This condition, known as eosinophilia, is often evident in laboratory tests during allergic events, such as asthma, hay fever, and allergic rhinitis.

The presence of increased eosinophils can indicate the activation of the immune system in response to allergens, as they release inflammatory mediators that contribute to the symptoms of an allergic response. Thus, a laboratory finding of increased eosinophils serves as an important marker for diagnosing and assessing the severity of allergic conditions.